Hitherto, laminated glasses are widely employed in the windowpanes of vehicles such as automobiles, aircrafts, buildings and the like since less fragments of broken laminated glasses shatter and laminated glasses are safe even though the laminated glass is subjected to an external impact to break. As such a laminated glass, there is given a laminated glass obtained by interposing an interlayer film for a laminated glass comprising, for example, a polyvinyl acetal resin such as a polyvinyl butyral resin plasticized with a plasticizer between at least a pair of glasses and unifying them.
An interlayer film for a laminated glass used for such laminated glasses contains an adhesion adjuster in order to adjust the adhesion between a glass sheet and an interlayer film for a laminated glass. An adhesion adjuster generally used was carbonate including alkali metal or alkaline earth metal.
However, there was a problem that the interlayer film for a laminated glass caused a whitening phenomenon and increased in a haze value when it absorbed moisture. In order to inhibit the whitening phenomenon due to the moisture absorption of the interlayer film for a laminated glass, there is disclosed, for example, a method of controlling the concentration of an alkali metal ion contained in the interlayer film for a laminated glass to below a certain value in Patent Document No. 1. Thereby, there is attained an interlayer film for a laminated glass which hardly whitens due to the moisture absorption.
However, in a side glass or an open edge type windshield and the like, in which an end of the laminated glass is exposed to atmosphere, since the interlayer film for a laminated glass tends to whiten from the periphery, an interlayer film for a laminated glass which does not cause whitening due to the moisture absorption even in more tough environment has been desired.    Patent Document No. 1: Japanese Patent No. 2999177